Hi I m curious if there is a Kotlin compiler configuration t

Question

Hi I m curious if there is a Kotlin compiler configuration that preserves some of the structure in a PSI in the FIR or a means to visit the PSI and associate the PSI to the FIR

Tracey Yoshima · Answer

In a code snippet like ```import java util Random fun method min Int max Int Int return Random nextInt max min + 1 ``` The PSI for the nextInt function call is `BINARY EXPRESSION` = gt on the Left hand side `PARENTHESIZED` = gt `BINARY EXPRESSION` Parenthesized expressions in source code may be unnecessarily wrapped at times like ` max min ` And I d like to preserve the source code formatting but the FIR removes the parentheses and only represents the function calls

dmitriy.novozhilov · Answer

No there isn t PSI is an CST concrete syntax tree which preserves original structure of code FIR is an AST abstract syntax semantics tree which represents meaning of code And the same FIR tree may be built from a number of different PSI trees There is no need for compiler to fully know original syntax structure Source elements in each FIR node is enough for compiler needs diagnostics reporting and line mapping collecting

dmitriy.novozhilov · Answer

What exactly you are trying to achieve

Tracey Yoshima · Answer

Ah okay that s fair I ve been translating the FIR to an OpenRewrite Kotlin v0 x <https docs moderne io concepts lossless semantic trees|LST> essentially a combination of the CST and AST with additional information like the language version stats on the formatting built tool info etc The work is to enable automated code remediation that leverages accurate type attribution while preserving the project s original stylistic formatting The remediations may include unifying code style implementing language best practices migrating from one language version to another or updating APIs from other projects I want to preserve the original source code so that a single unit of work what we call a recipe does not result in unexpected results even if the results are technically correct In the arbitrary example ` max ` excluding the parentheses does not cause any changes to the code but something like ` max min 2` without the parens `max min 2` would So I ve handled the parenthesis surrounding binary expressions in code but I was hoping for a means to use the existing FIR or PSI If a new version of `Kotlin` or a Kotlin plugin is released that includes API changes a `declarative recipe` will enable users to adopt the new version quickly